I asked awhile ago if anyone knew anything about this, which was
mentioned as a point of reference in Hamelitz. The "thunder," as
HaMelitz called it, was supposedly in June/July 1886.
Several people asked to be informed if I came up with anything.
The head of the Dolginov assn here in Israel has indeed heard of it
but all he knew was that it was a popular (rather than government
sponsored) event. He sounded very depressed to be even discussing
dolginov, as it reminded him that all the old people (who *really*
knew things) are gone. He said he'd send me an announcement before
there annual memorial service. End of story, for now.